An elderly woman who died of a heart attack after two men ransacked her home suffered a "truly terrifying ordeal", her family says.
Maureen Whale, 77, collapsed while on the phone to police as burglars raided her house in Bells Hill, Barnet, at 18:00 GMT on 4 December.
Post-mortem tests found she died from coronary heart disease brought on by the stress of the incident.
Her death is being treated as manslaughter.
Ms Whale lived alone at the house, which her family has lived in since 1928, and would have celebrated her birthday on Thursday.
In a statement, her nephew Laurence and niece Gina said: "It is heartbreaking that Maureen is no longer with us; this last week has felt like a nightmare.
"This must have been a truly terrifying ordeal for her. All we think about now, is of how vulnerable and scared she must of felt.
"She was a private, independent woman who was extremely proud. We urge people to come forward. The police need the names of those responsible."
Detectives believe the two burglars and a man acting as a look-out targeted three other properties in the area that evening - taking jewellery and Mrs Whale's small brown purse.
They are described as white and in their 20s.
Det Ch Insp Noel McHugh said: "I am in no doubt that the burglars knew that there was a lone female in the address.
"Criminals will have been talking about this wicked crime and now is the time to break the criminal code of 'not snitching' and offer these burglars up."
He said they were also looking for two witnesses on bikes, described as white and aged about 12 and 15, who spoke to officers at the scene.
The driver of a small four-door hatchback car, which travelled up Bells Hill towards Lexington Way, at 17:52, is also urged to come forward.
The vehicle may have been a Skoda Fabia and it drove directly past the suspects.